On-board inert gas generating air separation module recovery apparatus and method

Abstract

A method of recovering performance of an air separation module (ASM) is described. A recovery system includes an air source providing inlet air, a filter to output clean air and a heater heating the air. The ASM is coupled to the system and comprises a hollow fiber membrane to output nitrogen enriched air (NEA) exhaust. The method comprises operating the system with the air source and heater in a default condition; measuring an initial purity of NEA exhaust; adjusting the air source and/or heater based on the initial purity; operating the system after adjusting the air source and/or heater; returning the air source and heater to the default condition; measuring a recovered purity of NEA exhaust; and determining whether the recovered purity is within tolerance. If the recovered purity is within tolerance, system operation is terminated. If the recovered purity is not within tolerance, the steps are repeated.

What is claimed is: 
     
       1. A method of recovering air separation performance of an air separation module (ASM) via a recovery system, the recovery system including an air source configured to provide an air flow of high pressure inlet air to the recovery system, a filter configured to filter the inlet air and output clean air, a heater configured to heat either the inlet air or clean air, and an inlet connector and outlet connector configured to couple with the ASM, the ASM comprising a hollow fiber membrane configured to receive the heated clean air and output nitrogen enriched air (NEA) exhaust, the method comprising:
 a) operating the recovery system with the air source and heater in respective default conditions, wherein the air source outputs a default air flow rate and the heater outputs heated air having a default air temperature; 
 b) measuring an initial purity of NEA exhaust; 
 c) adjusting at least one of the air source and heater based on the measured initial purity of the NEA exhaust; 
 d) operating the recovery system after adjusting at least one of the air source and heater; 
 e) returning the air source and heater to their respective default conditions; 
 f) measuring a recovered purity of the NEA exhaust; and 
 g) determining whether the recovered purity is within predetermined tolerances; wherein:
 i) if the recovered purity is within predetermined tolerances, terminating operation of the recovery system; or 
 ii) if the recovered purity is not within predetermined tolerances, repeating steps c)-g). 
 
 
     
     
       2. The method of  claim 1  further comprising shutting down one or more aircraft systems prior to step a) and maintaining the aircraft systems without power until step g) i. 
     
     
       3. The method of  claim 1  further comprising connecting the ASM to the inlet and outlet connectors of the recovery system prior to step a). 
     
     
       4. The method of  claim 1  further comprising isolating the ASM from other aircraft systems. 
     
     
       5. The method of  claim 1  wherein the recovery system is incorporated within an aircraft on-board inert gas generating system (OBIGGS). 
     
     
       6. The method of  claim 5  wherein the respective default conditions of the air source and heater mimic standard OBIGGS operating conditions. 
     
     
       7. The method of  claim 1  wherein each of the initial purity and recovered purity is measured with an oxygen sensor. 
     
     
       8. The method of  claim 1  wherein the step of operating the recovery system after adjusting at least one of the air source and the heater is for a predetermined period of time before returning the air source and/or heater to the default condition. 
     
     
       9. The method of  claim 1  wherein the step of adjusting at least one of the air source and heater based on the measured initial purity of the NEA exhaust includes adjusting the air source to output an adjusted air flow rate about 1× to about 5× greater than the default air flow rate. 
     
     
       10. The method of  claim 9  wherein the adjusted air flow rate is about 2× to about 3× greater than the default air flow rate. 
     
     
       11. The method of  claim 1  wherein the step of adjusting at least one of the air source and heater based on the measured initial purity of the NEA exhaust includes adjusting the heater to output heated air having an adjusted air temperature between about 100° F. and about 300° F. 
     
     
       12. The method of  claim 11  wherein the adjusted air temperature is between about 200° F. and about 250° F.